Sheep and goat lines of Teladorsagia circumcincta (Nematoda): from allozyme to morphological identification.

Previous allozyme analyses demonstrated the existence of Teladorsagia circumcincta sheep and goat lines, based on the presence (goat line) or absence (sheep line) of an allele at the cathodic loci of malate dehydrogenase (MDH), with rapid migration (coded sR or super rapid) when starch gel electrophoresis was used. Simultaneous allozyme and morphometric characterization of individual worms from 3 natural populations harbored by goats were assessed. The nematodes with sR allele could be identified by a combination of measures of the dorsal ray of the bursa. Simple and fast morphological differentiation of worms with sR allele constitute an attractive tool for thorough studies on the frequency of these 2 types of worms and finally to assess the prevalence of goat and sheep lines.